Abbas Karimi Fard and Saeed Sedaghat
Drought stress is the most important factor to limiting access to high yield which this occurred by restricting growth in most stages of crop growth in arid and semiarid areas. In order to determine the best index and also identifying the best drought-resistant of bread wheat recombinant inbred lines (RILs), 79 RILs derived from a cross between a commercial variety Yecoro Rojo and NO.49 an Iranian local genotype were assessed using square lattice design under normal and water deficit conditions. Results of variance analysis of yield in two conditions showed that there was significant difference between under study genotypes for grain yield in non-stressed and normal conditions. Line 86 produced the highest grain yield in normal conditions (351.22 kg/ m2), while in drought conditions, the highest grain yield (212.295 kg/m2) from line 37. Different drought tolerance indices include Stress Tolerance (Tol), Mean Productivity (MP), Geometric Mean Productivity (GMP), Stress Susceptibility Index (SSI) and Stress Tolerance Index (STI), were evaluate based on grain yieldunder rain-fed (Ys) and normal irrigation (Yp) environments. MP, GMP, STI and had the highest correlation with yield in both conditions, selected as the best indices. Considering these three factors Lines 52, 65 and 86 were identified as the most tolerant to drought.
